The present invention refers to an apparatus for photometric analysis of coagulation behavior of blood, blood plasma or like fluids, and in particular to a cuvette container for holding a plurality of cuvettes which contain test samples for photometric measurement.
For photometric analysis of the coagulation behavior of blood or blood plasma or like fluids, it is generally known to use a cuvette container which is provided with a plurality of holding members adapted for receiving cuvettes which are of transparent material and contain a test sample. Suitably, the holding members have a cross section which corresponds to the usually rectangular cross section of the cuvettes. The photometric measurement is carried out by a photometer which includes a transmitter in form of a light source arranged in proximity of one narrow side of the cuvettes and a receiver in form of a light detector located in proximity of the other opposing narrow side of the cuvettes.
After completing the photometric analysis, the cuvettes are generally pulled out of the holding member, either manually, which is less desirable because of the obvious risk of contacting the cuvette content, or through suitable supply and discharge mechanisms by which the cuvettes are automatically fed and removed from the pertaining holding members. Regardless as to whether the removal is done manually or automatically, a withdrawal of the cuvettes requires an additional working step which usually takes a relatively long period so that extended pauses are experienced between successive photometric measurements. In particular, in case of analyzing a large number of test samples, as generally encountered in medical laboratories, the occurrence of such extended pauses is disadvantageous as it impedes an optimal utilization of the apparatus. Such drawbacks are compounded when using particular means such as gripper arms for automatically withdrawing the cuvettes because the gripper arm after picking up the cuvette has to travel back to an appropriate position for depositing the cuvette. This adds further to the actual discharge period.
U.S. Pat. No. 4,406,547 describes an apparatus for effecting photometric measurements by using a turntable which holds a number of cuvettes and rotates step by step for positioning the cuvettes for subsequent photometric measurement. Each cuvette is of particular design and includes at its upper periphery a supporting flange by which the cuvette is retained in position in a complementary holding member. After completing measurement, each cuvette is removed by a separate ejector which includes an L-shaped arm and a solenoid. When the solenoid is energized, the arm pulls the cuvette into an opening through which the cuvette can then fall down into a waste tank. An analyzer of this type is disadvantageous because it requires a relatively complicated ejector for removing the cuvettes, and because it is not suitable for use with conventional cuvettes; rather, the cuvettes as employed in this prior art are of particular design in order to allow proper positioning within the holding members.